Birth weight is that the weight of a baby at its birth. a toddler born small or large for fetal age (both of the 2 extremes) is assumed to possess an expanded danger of obesity in later life however it had been additionally demonstrated that this relationship is totally clarified by maternal weight. There are basically two distinct determinants for birth weight. The duration of gestation before birth, that is, the fetal age at which the kid is born, the prenatal rate of growth , generally measured in reference to what weight is predicted for any fetal age . a coffee birth weight are often caused either by a preterm birth (low fetal age at birth) or of the infant being small for fetal age (slow prenatal growth rate), or a mixture of both. a really large birth weight is typically caused by the infant having been large for fetal age . Environmental factors, including exposure of the mother to secondhand smoke, Other factors, like multiple births, where each baby is probably going to be outside the AGA (appropriate for gestational age), another so than the opposite.